Apparatus for milling and dispersing substances in liquid media



Feb. 8, 1966 R. J. SEVIN ETAL APPARATUS FOR MILLING AND DISPERSING SUBSTANCES IN LIQUID MEDIA 2 Sheets-Sheet 1 Filed Dec. 4, 1962 Feb. 8, 1966 R. J. SEVIN ETAL 3,233,835

APPARATUS FOR MILLING AND DISPERSING SUBSTANCES IN LIQUID MEDIA Filed Dec. 4, 1962 2 Sheets-Sheet 2 United States Patent 881,166 4 Claims. (Cl. 241-72) This invention relates to continuously operating apparatus for milling and dispersing relatively agglomerated substances into a liquid phase in finely divided form.

The apparatus according to the invention is of use, for instance, in wet milling and dispersing of charges for paper pulps, dyes or pigments, or charges for use in viscose, plastic pastes, paints, lacquers, inks and the like, for dispersing dyes in the manufacture thereof and in their application to the textile industry, and for refining pasty or liquid substances such as some foodstuffs, for instance, mustard or the like.

According to the present invention there is provided apparatus for milling and dispersing substances in liquid media, which comprises a bowl mounted for rotation on a vertical axis and divided into a plurality of superposed chambers by perforated partitions, the perforations in said partitions being of decreasing size for each successively higher partition, agitating means within each chamber, means for introducing the liquid media and the substances to be milled and dispersed into the lowermost chamber, and means for collecting the liquid media containing the milled and dispersed substances, after they have passed through the chambers, upwardly, at the top of the bowl.

In using the said apparatus the materials are introduced continuously into the bottom chamber move progressively, as they become finer, through the partitions, finally to be collected in the required state of dispersion at the top of the bowl.

To intensify the milling action, milling agents may be placed in some or all of the chambers of the bowl. Such milling agents may or may not be of the same size and nature in the various chambers, the only condition applying to them being that they should be large enough not to pass through the partitions bounding the chambers in which they are disposed.

The extent of milling achieved by the use of the apparatus may be controlled by separate or simultaneous control of various factors, such as the concentration of solid substance in the liquid media, the concentration and nature of any milling agents used, and the speed at which the centrifuging bowl is caused to rotate. The liquid contaning the dispersed particles may be removed by allowing it to overflow from the bowl but it is preferably removed by means of a suction nozzle, the position of which may be varied to provide a further control.

A specific form of appartus according to the invention is illustrated in the accompanying drawing, which shows a view of the apparatus in vertical axial section.

FIGURE 1 is a view in vertical axial section of an apparatus according to the invention.

FIG. 2 is a top plan view of an agitating element.

FIG. 3 is a view in section taken along the line 33 of the FIGURE 2.

Referring to the drawing, the appartus comprises a base 1 having a bearing 2 receiving, a vertical shaft 3 having a driving pulley 4 connected to a motor 6 by way of a transmission unit 5, preferably of the variable-speed type. The shaft 3 is rigidly secured to a disc 7 to which a centrifuging bowl 8 is secured. The bowl 8, which is preferably cylindrical, comprises, in the example illustrated, four parts, 9, Ill, 11 and 12 interconnected by means of flanges 13 which clamp partitions 14-, 15 and 16 dividing the bowl 8 into chambers 8a, 8b and 8c. Each such partition is fromed with numerous fine perforations after the fashion of a screen, the perforations decreasing in size from one partition to the next upwards in the bowl =8. The part 9 has a base 9a, and the top part 12 has an inwardly directed flange 12a.

The bowl 8 is surrounded by a casing 17 which is secured to the base 1 and whose cover 17a encompasses a tube 13 extending vertically and coaxially of the bowl 8. The tube 18 extends through the partitions 16, 15, 14 with slight clearance by way of respective apertures 16a, 15a, 14a in the partitions.

An agitating element 19a, 19b, 190 is connected to the tube 18 respectively in each chamber 8a, 8b, 80. Preferably, each such agitating element takes the form of a disc formed with apertures and associated inclined fins as described in the French Patent No. 1,309,367, filed October 4, 1961, and shown in FIGURES 2 and 3. In the example illustrated, the tube 18 is stationary but it may, of course, be coupled with a motor for rotation in either direction around its axis, preferably at a variable speed, for instance, through the agency of a transmission unit similar to the transmission unit 5. The tube 18 has at its top a funnel 220 for the introduction of products to be treated, and terminates in the bottom chamber 8:: above the base member 9a.

The cover 17a also carries a sleeve 21 comprising a nut 22 rigidly secured to a hand-control wheel 23; engaging in the nut 22 is a screw-threaded tube 24 having at one end a curved intake nozzle 25, which terminates in the top part 12 of the bowl 8, and at the other end a pipe 26 connected to a pump 27 for removal of the mixed product.

The disc 19 as shown in FIGS. 2 and 3 is pierced with a number of concentric rows of apertures 29a, 29b, 29c evenly spaced in each row. Associated with each aperture is a fin formed by a dihedron-like plate and secured to the disc in such a manner that it covers a part of the corresponding aperture. For the row of apertures 29a, the fins 30a are all located on a same side of the disc, for the other rows 29b, 290, the fins 30b and 300 respectively, are alternatively situated on the same side as the fins 30a and on the opposite side, as shown.

The apparatus just described operates as follows:

After the appropriate quantities of milling agents have, where applicable, been placed in the required chambersfor instance, milling agents such as are described in copending US. Patent application No. 238,916, filed November 20, l962the mixture of the liquid and of substances or agglomerates which are to be milled and dispersed in the liquid, starts to be introduced through the tube 18, and the bowl 8 is rotated. The mixture passes first to the bottom chamber 8a to be milled and dispersed by the agitator disc 1911, the substance being treated describing figure-of-eight movements as indicated by arrows in the drawing. The liquid, entraining with it the particles fine enough to pass through the screen 14, progressively goes into the chamber 3b where it is treated by the agitator 19b in a similar manner. The liquid, carrying still finer particles, enters the chamber to be treated by the agitator 19c; finally, a product which has been milled and dispersed to the required extent passes through top screen 16 to be sucked into the nozzle 25.

The centrifugal force produced by rotation of the bowl 8 tends to make the substances therein collect near the bowl side wall in a peripheral space whose thickness decreases With distance away from the base of the bowl, as diagrammatically illustrated in the drawing. The rate of flow at which the substances are delivered from the bowl 8 can be controlled by variation of the distance between the aperture of the nozzle 25 and the bowl side wall. AS already stated, control of the results obtained may be provided by control of other factors, such as the concentration and nature of the milling agents, and the speed of rotation of the bowl.

We claim as our invention:

1. An apparatus for milling and dispersing substances in liquid media comprising in combination a frame, a bowl mounted on said frame for rotation about a vertical axis and divided into a plurality of superposed chambers by perforated partitions, the perforations in said partitions being of decreasing size for each successively higher partition, agitating means within each chamber, means for introducing the liquid media and the substances to be milled and dispersed into the lowermost chamber, suction means for removing liquid media containing the milled and dispersed substances from the uppermost chamber of said bowl, and means for varying the distance between said suction means and the axis of rotation of said bowl, whereby the rate of flow at which said media and substances are removed from said bowl may be controlled.

12. An apparatus for milling and dispersing substances in liquid media comprising in combination a frame, a bowl mounted for rotation on said frame about a vertical axis, said bowl having an upper end wall provided with a central opening and being divided into a plurality of superposed chambers by perforated partitions, the pertorations in said partitions being of decreasing Size for each successively higher partition, agitating means within each chamber, means for introducing the liquid media and the substances to be milled and dispersed into the lowermost chamber of said bowl; a suction nozzle protruding through said central opening into the uppermost chamber of said bowl and means supported by said frame for varying the distance between said nozzle and the axis of rotation of said bowl.

3. An apparatus as claimed in claim 2 wherein each said partition is provided with a central aperture, said apertures being centered onto the axis of rotation of said bowlyatu-be supported by said frame, passing through said central opening in said upper wall and through said apertures, the lower end of said tube being located at a distance :from the bottom of said bowl whereby said tube constitutes said means for introducing said liquid media and said substances into said lowermost chamber and said agitating means being carried by said tube.

5 4. An apparatus as claimed in claim 3 wherein said means for varying the distance between said nozd'le and the axis of rotation of said bowl includes a casing surrounding said bowl, "a cover on said casing, a sleeve secured to said cover, adapted to guide said nozzle, and

0 being provided with a screw threaded portion, and a nut mounted for rotation on said sleeve adapted to engage said screw threaded portion.

References Cited by the Examiner 5 UNITED STATES PATENTS 1,956,293 4/1934 Klein 241-172 2,578,274 12/1951 Weigharn 241-46 FOREIGN PATENTS 0 592,105 2/1934 Germany.

ROBERT C. RIORDON, Primary Examiner. J. SPENCER OVERHOLSER, Examiner. 

1. AN APPARATUS FOR MILLING AND DISPERSING SUBSTANCES IN LIQUID MEDIA COMPRISING IN COMBINATION A FRAME, A BOWL MOUNTED ON SAID FRAME FOR ROTATION ABOUT A VERTICAL AXIS AND DIVIDED INTO A PLURALITY OF SUPERPOSED CHAMBERS BY PERFORATED PARTITIONS, THE PERFORATIONS IN SAID PARTITIONS BEING OF DECREASING SIZE FOR EACH SUCCESSIVELY HIGHER PARTITION, AGITATING MEANS WITHIN EACH CHAMBER, MEANS FOR INTRODUCING THE LIQUID MEDIA AND THE SUBSTANCES TO BE MILLED AND DISPERSED INTO THE LOWERMOST CHAMBER, SUCTION MEANS FOR REMOVING LIQUID MEDIA CONTAINING THE MILLED AND DISPERSED SUBSTANCES FROM THE UPPERMOST CHAMBER OF SAID BOWL, AND MEANS FOR VARYING THE DISTANCE 